The primary goal of this core is to aid the investigators of the individual projects in generation of sufficient numbers of genetically modifled mice to complete their projects in a timely and efficient fashion. The mouse breeding and genotyping core will be responsible for 1) overseeing the generation and characterization of genetically modified mice; 2) maintenance, expansion and intercrossing of mice lines as needed; and 3) optimization of genotyping protocols for mice containing multiple recombinant genes.